Asynchronous transfer mode (ATM) technology is rapidly being recognized as the technology of choice for broad-band data communications. ATM cells having a fixed number of bytes can efficiently accommodate multimedia traffic such as video, voice and data.
ATM cell traffic between nodes in an ATM network is carried on what are known as virtual connections (VC) Traffic from end user to end user through a plurality of intermediate nodes is carried on virtual channel connections (VCC). Since traffic from several sources may have a common destination it is known to combine virtual channel connections onto a virtual path connection (VPC) in order to simplify the processing of traffic through the network. When virtual channel connections are aggregated onto a virtual path connection, the individual virtual channel connections are essentially transparent to the intermediate ATM nodes and this allows a simpler networking model and higher manageability. A virtual path connection is defined as a logical grouping of multiple virtual channel connections into one virtual connection.
Although the aggregation of virtual channel connections onto a common path simplifies traffic management, concerns have been expressed that individual virtual channel connections may not all be treated fairly when aggregated onto a virtual path connection. Demirtjis and Petr (IEEE IC3N, 1995 "How to Encourage Cheating with Virtual Path Policing in ATM Networks") have found that virtual channel connections which are in compliance with predefined transmission parameters may be adversely affected by non-compliant traffic when aggregated onto a virtual path.
U.S. Pat. N0. 5,629,928 which issued May 13, 1997 to Calvignac et al discloses one technique for controlling traffic flow in a virtual path communication system wherein queues allocated as needed from a pool of free queues are used to store all incoming data cells having the same virtual channel identifier.